One of my highlight of Neuroscience 2010 - the huge bash for 31000 neuroscientists which I recently attended in San Diego - was a talk by Valentin Nagerl about nano-scale imaging of spines. I spend a lot of my time imaging dendritic spines on a confocal microscope, and pretty fuzzy they look sometimes - not because of any issues with our microscope I hasten to add, but just because I'm trying to image something whose size is of the same order as the wavelength of light. So I was just stunned to see the beautiful images of spines that Dr Nagerl obtained using STED. This all works with doughnuts apparently. Doughnuts of light, of a different wavelength, which you interleave at very high frequency with your actual illumination spot. This "prerelaxes" the electrons in your dye, with the result that you get a *very* small spot scanning your sample.
Here are some images from his latest paper (Nagerl UV, Bonhoeffer T (2010) Imaging living synapses at the nanoscale by STED microscopy. J Neurosci 30:9341-9346). Are they not lovely?